STMicroelectronics TS921IDT

Overview

TS921IDT from STMicroelectronics is a rail-to-rail input/output single BiCMOS operational amplifier optimized for 3 V and 5 V battery-powered audio systems. It delivers 80 mA output current into 32 Ω loads, features 9 nV/√Hz input noise at 1 kHz, 4 MHz gain-bandwidth product, 1 V/μs slew rate, and operates from 2.7 V to 12 V supply. It serves as a high-fidelity headphone amplifier in portable multimedia devices.

For engineers reviewing the TS921IDT datasheet, TS921IDT pinout, TS921IDT application, or TS921IDT equivalent, key selection criteria include rail-to-rail output swing into low-impedance loads, low-noise performance below 10 nV/√Hz, thermal resistance of 125 °C/W (SO-8), latch-up immunity, and ESD protection rated at 1.5 kV HBM.

Technical Context

The TS921IDT employs a BiCMOS input stage enabling rail-to-rail common-mode input range (V_DD − 0.2 V to V_CC + 0.2 V) and rail-to-rail output swing within 100 mV of each rail under 32 Ω load. Its architecture supports stable operation with capacitive loads up to 500 pF without external compensation.

It achieves 80 dB CMRR and PSRR across 2.7–12 V supply range, maintains 0.005% THD+N at 1 kHz with 2 V_pk-pk output into 600 Ω, and exhibits 2 μV/°C input offset drift - critical for precision audio front-ends and instrumentation amplifiers operating over industrial temperature range (−40 °C to +125 °C).

Key Specifications

Pinout & Package

TS921IDT is supplied in SO-8 (Small Outline Integrated Circuit, 8-pin) package per JEDEC MS-012, with 1.27 mm pitch, body size 4.9 × 6.0 mm, and thermal resistance R_thJA = 125 °C/W.

Key Features

Applications

Equivalent & Alternatives

The following parts are listed as comparable options for similar rail-to-rail audio amplifier applications.

Compared with LMV321IDBVR and MCP6001T-E/OT, TS921IDT uniquely combines 80 mA output drive, rail-to-rail swing, and 9 nV/√Hz noise - making it the only option among the three qualified for battery-powered headphone amplification without external buffering.

Availability

TS921IDT is available at Aetrix Electronics and suitable for portable audio systems, industrial instrumentation front-ends, and embedded actuator control circuits requiring stable component supply across extended temperature ranges and long production lifecycles.

Supply support for TS921IDT includes scheduled delivery planning, volume procurement assistance, BOM continuity management, traceable sourcing, and lifecycle availability coordination for OEM customers, industrial embedded developers, connected-device designers, and electronics production programs.

Manufacturer

STMicroelectronics is a global semiconductor leader headquartered in Geneva, Switzerland, designing and manufacturing analog, mixed-signal, power, and microcontroller solutions for industrial, automotive, and consumer markets.

The TS921 belongs to ST's precision rail-to-rail op-amp product line, engineered specifically for low-voltage, high-output-current audio and sensing applications where noise, distortion, and drive capability are design-critical parameters.

FAQ

What is the maximum capacitive load the TS921IDT can drive without oscillation?

The TS921IDT is specified stable with capacitive loads up to 500 pF when configured in unity-gain configuration, as confirmed in the datasheet's "Electrical Characteristics" section and Figure 12 (open-loop gain/phase vs. frequency with C_L = 500 pF). This eliminates need for isolation resistors in most PCB layout scenarios involving short traces or small ceramic decoupling caps.

Does TS921IDT support true single-supply operation with input signals near ground?

Yes. The TS921IDT features rail-to-rail input common-mode range extending to V_EE − 0.2 V (i.e., −0.2 V below ground when referenced to GND), allowing direct amplification of signals down to 0 V in single-supply 3 V systems - critical for microphone preamp or sensor signal conditioning without level-shifting.

What is the thermal performance limitation of TS921IDT in SO-8 package at 80 mA continuous output?

In SO-8 package, TS921IDT has R_thJA = 125 °C/W. At 80 mA output into 32 Ω with 3 V supply, power dissipation reaches ~120 mW. Under still-air conditions, this yields ~15 °C junction-to-ambient rise - well within the 150 °C max junction temperature limit and compatible with operation at +125 °C ambient when board copper area is ≥1 cm².

Can TS921IDT replace legacy LM358 in existing designs without modification?

No. While both are single op-amps, TS921IDT requires different biasing: its rail-to-rail input stage accepts signals at GND, but its output cannot swing fully to V_CC or GND under heavy load (e.g., 100 mV headroom into 32 Ω). LM358 lacks rail-to-rail capability entirely. Direct replacement requires verifying input common-mode range, output swing margins, and stability with existing feedback networks.